This invention relates to a supporting system suitably usable, for example, in a fine-motion stage of a wafer stage incorporated into a semiconductor exposure apparatus.
FIG. 28 is a perspective view of a wafer rough-motion stage of a supporting system used in a semiconductor exposure apparatus. In this wafer rough-motion stage, a Y yaw guide 202 is fixed on a base table 201, and a Y stage 203 which is guided by a side face of the Y yaw guide 202 and a top face of the base table 201 is slidably supported on the base table 201 by means of an air slide (not shown) along a Y direction. The Y stage 203 consists mainly of four components, that is, two X yaw guides 204, a Y large slider 205 and a Y small slider 206. The Y large slider 205 is opposed to the side face of the Y yaw guide 202 and the top face of the base table 201, through air pads (not shown) provided at the side and bottom faces thereof. The Y small slider 206 is opposed to the top face of the base table 201 through air pads (not shown) provided at the side face thereof. With this structure, the Y stage 203 as a whole is supported on the top face of the base table 201 and the side face of the Y yaw guide 202, slidably in the Y direction.
On the other hand, an X stage 210 is guided by the top face of the base table 201 and the side faces of the two X yaw guide 204 which are components of the Y stage 203. The X stage 210 is provided so as to surround the X yaw guide 204 of the Y stage 203, around the X axis. The X stage 210 is supported slidably, in the X direction, by means of an air slide (not shown). The X stage 210 consists mainly of for components, that is, two X stage side plates 211, an X stage top plate 212 at the top end, and an X stage bottom plate 213. The bottom plate 213 is opposed to the top face of the base table 201 through air pads (not shown) which are provided at the bottom face of the bottom plate. The two X stage side plates 211 are opposed to the side faces of the two X yaw guides 204, which are components of the Y stage 203, through air pads (not shown) provided at the side faces of the side plates The bottom face of the X stage top plate 212 and the top face of the X yaw guide 204, as well as the top face of the X stage bottom plate 213 and the bottom face of the X yaw guide 204 are kept out of contact with each other. With this structure, the X stage 210 as a whole is supported at the side faces of the two X yaw guides 204 and the top face of the base table 201, slidably in the X direction.
As regards the driving mechanism, there are multiple-phase coil switching type linear motors 214 and 215, one for X driving and two for Y driving. A stator 216 comprises a plurality of coils 217 arrayed in the stroke direction and being inserted into a frame 218. A movable element 219 comprises a magnet unit of box shape. In accordance with the position of the movable element 219, electric currents are selectively applied to coils 217 of the stator 216, whereby a thrust is produced. Mounted on the top of the X stage top plate 212 is a fine-motion stage 221 shown in FIGS. 29 and 30.
The fine-motion stage 221 serves to position a wafer W (workpiece) placed on the X stage top plate 212, with respect to Z tilt and xcex8 direction. By means of three Z suspension driving units 222-1 to 222-3 provided at the peripheral portion, the wafer stage top plate 223 is supported and positioned with respect to Z tilt direction. A universal joint 224 provided at the central portion serves to confine the freedom to prevent shift of the wafer stage top plate 223 in X and Y directions.
The Z suspension driving units 222-1 to 222-3 each comprises an air cylinder 226 for supporting the weight of the wafer stage top plate 223, and a Z linear motor 230 for applying a force, in the Z direction, to the wafer stage top plate 223.
The Z linear motor 230 comprises a flat coil 231 having a major or lengthwise side parallel to a horizontal line, four magnets 232 opposed, through a gap, to the major side of the flat coil 231, and two yokes 233 for circulating the magnetic flux of the magnets 232. The flat coil 231 is fixed to the X stage top plate 212, and the magnets 232 and the yokes 233 are fixed as a unit to the wafer stage top plate 223. As an electric current is applied to the flat coil 231, a force in the Z direction operates between the coil 231 and the integral structure of the magnet 232 and the yoke 233.
The air cylinder 226 comprises a supporting rod 227 and a rubber film 228. The rubber film 228 is provided at the lower portion of the wafer stage top plate 223, and it serves to define an air chamber 229 between the lower portion of the top plate 223 and the supporting rod 227. Airs are supplied through a supply port, not shown. The supporting rod 227 has an end fixed to the flat coil 231, and the other end is coupled to the rubber film 228. As a result, the weight of the wafer stage top plate 223 is supported from the X stage 210 and through the flat coil 231, the supporting rod 227 and the air chamber 229. The air chamber 229 provides a soft spring in the Z direction, so that vibration in the Z direction can be substantially blocked.
The Z linear motor 230 does not bear the function of weight support but it operates solely for the position control. With this structure, an electric current which nay otherwise cause a problem of heat generation is not flown thereto.
The universal joint 224 comprises an outer ring 236 fixed to the X stage top plate 212, an inner ring 237 fixed to the wafer stage top plate 223, and a guide 238 for slidably guiding the outer and inner rings 236 and 237. The guide 238 may comprise an air guide, for example, having an air gap of a few microns. This air gap has a ring-like shape, and the inner ring 237 and the outer ring 236 as well as the X stage top plate 212 and the wafer stage top plate 223 are guided for slidable motion along the Z and xcex8 directions. The height of the guide 238 in the Z direction is set lower, such that motion of the inner and outer rings 234 and 236 as well as the top plates 212 and 223 in the the direction is allowed.
Although not shown in the drawings, a mechanism similar to the Z linear motor 230, including a flat coil 231 having a major or lengthwise side parallel to the vertical line, is provided, so that the wafer stage top plate 223 can be moved in the xcex8 direction.
Mounted on the side face of the wafer stage top plate 223 is a square mirror (not shown) which enables precision measurement of the position, in six-axis direction, of the wafer stage top plate 223 by use of a laser interferometer.
In the structure described above, in conventional exposure apparatuses, a wafer W is precisely positioned with respect to the X, Y, Z, xcex8 and tilt directions, by means of a control system (not shown) and by applying appropriate electric control to coils of rough-motion x, rough-motion Y, fine-motion Z1, fine-motion Z2, fine-motion Z3 and fine-motion xcex8. Then, an exposure process is performed by using exposure means (not shown), whereby a pattern of an original (not shown) is sequentially printed on a wafer W.
In accordance with an aspect of the present invention, there is provided a supporting system, comprising: a carrying nicer for carrying thereon a workpiece; and a supporting mechanism having a magnet, for supporting a weight of said carrying member; wherein a supporting force to be provided by said magnet does not change with a shift of said carrying member along a plane perpendicular to a direction in which the weight is supported.
The supporting mechanism may have a magnet and a magnetic member, wherein said magnet and said magnetic member may differ from each other in respect to a size in a direction perpendicular to a direction in which a force operates between said magnet and said magnetic member.
The supporting mechanism may include plural magnets for mutually operating a force, wherein one magnet differs from another magnet in respect to a size in a direction perpendicular to a direction in which a force operates between the magnets.
The supporting mechanism may include a magnetic member and an electromagnet, wherein said magnetic meter and said electromagnet may differ from each other in respect to a size in a direction perpendicular to a direction in which a force operates between said magnetic member and said electromagnet.
Each of said magnetic member and said electromagnet may comprise a layered structure of thin magnetic material plates.
There may be a controller for controlling an electric current to said electromagnet.
There may be a detector for detecting a clearance between said electromagnet and said magnetic member, and a circuit for feedback of a signal related to the detected clearance to an electric current to be applied to said electromagnet.
There may be a position controller for positioning said carrying member, wherein plural supporting mechanism are disposed so as not to produce a moment to said position controller.
In accordance with another aspect of the present invention, there is provided a supporting system, comprising: a carrying meter for carrying thereon a workpiece; and a supporting mechanism for supporting said carrying member, said supporting mechanism having a first element for producing a resisting force to a shift in a supporting direction, and a second element for producing a force for increasing the shift in the supporting direction; wherein said second element can produce a force for moving said carrying member downwardly.
The supporting mechanism may include a spring element and a magnet element.
Adjacent a workpiece processing position for the workpiece, a weight of said carrying masher and a combined force of said first and second elements may be substantially equal to each other.
In accordance with a further aspect of the present invention, there is provided a supporting system, comprising; a carrying maker for carrying a workpiece thereon; and a supporting mechanism for supporting said carrying member from a workpiece transfer position to a workpiece processing position, said supporting mechanism having a first element for producing a resisting force to a shift in a supporting direction, and a second element for producing a force to increase a shift in the supporting direction.
The second element for producing a force to increase the shift may produce a force to move said carrying member downwardly.
Adjacent to the workpiece processing position, the weight of said carrying member and a combined force of said first and second elements may be approximately equal to each other.
The force to be produced by said second element may be larger at the transfer position than at the workpiece processing position.
The first and second elements may include a spring element and a magnet element.
In accordance with a yet further aspect of the present invention, there is provided a supporting system, comprising: a carrying member for carrying a workpiece thereon; and a supporting mechanism for supporting said carrying member from a workpiece transfer position to a workpiece processing position, said supporting mechanism having a spring element and a magnet element; wherein, adjacent the workpiece processing position, the weight of said carrying member and a combined force of said spring element and said magnet element are approximately equal to each other, and wherein said magnet element has a magnet with a clearance which is smaller at the transfer position than at the workpiece processing position.
At a certain position, the clearance of the magnet of said magnet element may be smaller than that at the workpiece processing position, and at that position, the weight of said carrying member and the combined force of said spring element and said magnet element may be approximately equal to each other.
An absolute value of a changing rate of the force of said magnet element with respect to a change in clearance of the magnet, adjacent the workpiece processing position, may be set smaller than an absolute value of a changing rate or the force of said spring element with respect to a change in the clearance of the magnet.
In accordance with a still further aspect of the present invention, there is provided a supporting system, comprising: a carrying member for carrying a workpiece thereon; and a supporting mechanism for supporting said carrying member from a workpiece transfer position to a workpiece processing position, said supporting mechanism having a spring element and a magnet element; wherein, adjacent the workpiece processing position, the weight of said carrying member and a combined force of said spring element and said magnet element are approximately equal to each other, and wherein said magnet element has a magnet with a clearance which is larger at the transfer position than at the workpiece processing position.
At a certain position, the clearance of the magnet of said magnet element may be larger than that at the workpiece processing position, and at that position, the weight of said carrying member and the combined force of said spring element and said magnet element may be approximately equal to each other.
An absolute value of a changing rate of the force of said magnet element with respect to a change in clearance of the magnet, adjacent the workpiece processing position, may be set larger than an absolute value of a changing rate of the force of said spring element with respect to a change in the clearance of the magnet.
In accordance with a yet further aspect of the present invention, there is provided a supporting system, comprising: a carrying member for carrying a workpiece thereon; and a supporting mechanism for supporting said carrying member from a workpiece transfer position to a workpiece processing position, said supporting mechanism having a spring element and a magnet element; wherein an absolute value of a changing rate of the force of said magnet element with respect to a change in clearance of the magnet, adjacent the workplace processing position, is set smaller than an absolute value of a changing rate of the force of said spring element with respect to a change in the clearance of the magnet.
In accordance with a still further aspect of the present invention, there is provided a supporting system, comprising: a carrying member for carrying a workpiece thereon; and a supporting mechanism for supporting said carrying member from a workpiece transfer position to a workpiece processing position, said supporting mechanism having a spring element and a magnet element; wherein an absolute value of a changing rate of the force of said magnet element with respect to a change in clearance of the magnet, adjacent the workpiece processing position, is set larger than an absolute value of a changing rate of the force of said spring element with respect to a change in the clearance of the magnet.
In accordance with a still further aspect of the present invention, there is provided a supporting system, comprising: a carrying member for carrying a workpiece thereon; and a supporting mechanism for supporting said carrying member from a workpiece transfer position to a workpiece processing position; wherein, adjacent the transfer position, the weight of said carrying member and a force to be applied to said carrying member are substantially balanced, and wherein, adjacent the workpiece processing position, the weight of said carrying member and a force to be applied to said carrying member are substantially balanced.
The supporting mechanism may have a first element for producing a resisting force to a shift in a supporting direction, and a second element for producing a force for increasing the shift in the supporting direction.
The supporting mechanism may include a spring element and a magnet element.
In accordance with another aspect of the present invention, there is provided an exposure apparatus, comprising: a carrying member for carrying thereon a workpiece; and a supporting mechanism having a magnet, for supporting a weight of said carrying member; wherein a force to be applied to said magnet does not change with a shift of said carrying member along a plane perpendicular to a direction in which the weight is supported.
In accordance with a further aspect of the present inventions there is provided an exposure apparatus, comprising: a carrying member for carrying thereon a workpiece; and a supporting mechanism for supporting said carrying member, said supporting mechanism having an element for producing a force to increase/decrease a shift in a supporting direction, wherein, as the shift in the supporting direction increases, said carrying member is moved downwardly.
In accordance with a further aspect of the present invention, there is provided an exposure apparatus, comprising: a carrying member for carrying a workpiece thereon; and a supporting mechanism for supporting said carrying member from a workpiece transfer position to a workpiece processing position, said supporting mechanism having a first element for producing a resisting force to a shift in a supporting direction, and a second element for producing a force to increase a shift in the supporting direction.
In accordance with a still further aspect of the present invention, there is provided an exposure apparatus, comprising: a carrying member for carrying a workplace thereon; and a supporting mechanism for supporting said carrying member from a workpiece transfer position to a workpiece processing position, said supporting mechanism having a spring element and a magnet element; wherein, adjacent the workpiece processing position, the weight of said carrying member and a combined force of said spring element and said magnet element are approximately equal to each other, and wherein said magnet element has a magnet with a clearance which is smaller at the transfer position than at the workpiece processing position.
In accordance with a still further aspect of the present invention, there is provided an exposure apparatus, comprising: a carrying member for carrying a workpiece thereon; and a supporting mechanism for supporting said carrying member from a workpiece transfer position to a workpiece processing position said supporting mechanism having a spring element and a magnet element; wherein, adjacent the workpiece processing position, the weight of said carrying member and a combined force of said spring element and said magnet element are approximately equal to each other, and wherein said magnet element has a magnet with a clearance which is larger at the transfer position than at the workpiece processing position.
In accordance with a yet further aspect of the present intention, there is provided an exposure apparatus, comprising: a carrying member for carrying a workpiece thereon; and a supporting mechanism for supporting said carrying member from a workpiece transfer position to a workpiece processing position, said supporting mechanism having a spring element and a magnet element; wherein an absolute value of a changing rate of the force of said magnet element with respect to a change in clearance of the magnet, adjacent the workpiece processing position, is set smaller than an absolute value of a changing rate of the force of said spring element with respect to a change in the clearance of the magnet.
In accordance with a yet further aspect of the present invention, there is provided an exposure apparatus, comprising; a carrying member for carrying a workpiece thereon; and a supporting mechanism for supporting said carrying member from a workpiece transfer position to a workpiece processing position, said supporting mechanism having a spring element and a magnet element; wherein an absolute value of a changing rate of the force of said magnet element with respect to a change in clearance of the magnet, adjacent the workpiece processing position, is set larger than an absolute value of a changing rate of the force of said spring element with respect to a change in the clearance of the magnet.
In accordance with a still further aspect of the present invention, there is provided an exposure apparatus, comprising; a carrying member for carrying a workpiece thereon; and a supporting mechanism for supporting said carrying meter from a workpiece transfer position to a workpiece processing position: wherein, adjacent the transfer position, the weight of said carrying member and a force to be applied to said carrying member are substantially balanced, and wherein, adjacent the workpiece processing position, the weight of said carrying member and a force to be applied to said carrying member are substantially balanced.
In accordance with an aspect of the present invention, there is provided a device manufacturing method, comprising the steps of: preparing an exposure apparatus as recited above; applying a resist to a wafer; exposing the wafer by use of the exposure apparatus; and developing the exposed wafer.
These and other objects, features and advantages of the present invention will become more apparent upon a consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings.